1. Field of the Invention
The present invention generally relates to an auto focus (AF) module of an image capture device, and more particularly to an auto focus module which can prevent lens jamming resulting from malfunction.
2. Description of Related Art
Modern digital image capture devices are widely applied in digital cameras, digital video cameras, video lenses for home use or conference use etc. image sensors on a circuit board are integrated with a lens module to receive optical image signals and to transfer the optical image signals to electronic signals via photoelectric technologies to render optical images suitable for storage, identification and processing. Conventional auto focus lens module uses a stepping motor to drive a lens into a focus position. In order to proceed auto focus action, the lens must move in directions along a lens axis. In some unusual circumstances, such as malfunctions of the auto focus lens module or failures of lens position detectors, the lens of the auto focus lens module would continue moving over the predetermined stop position until the lens jams such that even the stepping motor driving the lens in a reverse direction can not release the lens from jamming resulting in malfunction of the auto focus lens module and render the auto focus lens module unable to focus.
The invention provide an auto focus module which can prevent the lens from jamming resulting from malfunction to resolve the problem of lens jamming caused by the malfunctions or unstable condition of lens position sensors and controller